Hydraulic actuator for operating the apron and ejector of earthmoving scrapers



y 9 c. A. GUST-AFSON 2,677,202

HYDRAULIC ACTUATOR FOR OPERATING THE APRON AND EJECTOR 0F EARTH-MOVING SCRAPERS Filed April 5, 1951 3 Sheets-Sheet 1 E INVENTOR; CARL A. Cl/STAFJOA/ .ABY

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AT TORZVE Y May 4. 1954 c. A. GUSTAFSON 2,677,202

HYDRAULIC ACTUATOR FOR. OPERATING THE APRON AND EJECTOR OF- EARTHMOVING SCRAPERS Filed April 3, 1951 3 Sheets-Sheet 2 INVENTOR. CARL A. GWSTAFJO/V ATTORNEY May 4. 1954 c. A. GUSTAFSON 2 7,

HYDRAULIC ACTUATOR FOR OPERATING THE APRON AND EJECTOR 01- EARTH-MOVING SCRAPERS Filed April 5, 1951 5 Sheets-Sheet 3 INVENTOR. CARL A. GUJTAFJO/V Patented May 4, 1954 HYDRAULIC ACTUATOR FOR OPERATING THE APRON AND EJECTOR OF EARTH- MOVING SCRAPERS Carl A. Gustafson, Peoria, 111., assignor to Caterpillar Tractor 00., Peoria, Ill., a corporation of California Application April 3, 1951, Serial No. 218,979

4 Claims.

This invention relates to earthmoving scrapers in general, and more particularly to hydraulically actuated scrapers in which the ejector and apron are operated by a single jack.

One type of earthmoving scraper now commonly employed for collecting and moving large quantities of earth and like materials comprises a large bowl or body member supported on ground engaging wheels and having a draft connection by means of which it may be drawn by a tractor unit. The bowl is provided with a scraping edge adjacent its forward portion and may be lowered, bringing it into contact with the ground to efiect collection of earth which is deposited in the bowl. The rear wall of the bowl is formed as an ejector which is adapted to be advanced forwardly through the bowl to discharge its contents after the scraper has been drawn to the proper place for unloading. Th front of the bowl is normally closed by a gate-like device usually referred to as an apron which is adapted to be swung upwardly or opened during loading and unloading of the scraper bowl. Operation of the ejector and apron, as well as raising and lowering of the bowl with relation to the ground, are all desirably controlled from the tractor through hydraulic controls conveniently located adjacent the tractor operator. The hydraulic controls include a suitable engine driven fluid pump and a control valve for directing fluid under pressure through suitable conduits to one or more double-acting hydraulic jacks associated with each of the movable parts of the scraper.

In a scraper of this type in which each of the movable scraper parts is actuated by a separate hydraulic jack or jacks, one of the principal difiiculties encountered has been that the power requirements for operating the apron and ejector simultaneously requires a relatively expensive hydraulic pump having adequate output at a high operating pressure. In addition a relatively complex control system is required which is expensive to manufacture and difficult to maintain in operation.

It is, therefore, an object of the present invention to provide a scraper of the kind described wherein the ejector and apron are actuated by a single hydraulically actuated jack.

It is another object of the present invention to provide a scraper of the kind described in which a mechanical linkage is provided for operating the apron in timed relationship to movement of a single hydraulic jack provided for actuating the ejector.

Other objects and advantages of this invention will be made apparent in the following description wherein reference is made to the accompanying drawings.

In the drawings:

Fig. 1 is a view in side elevation with parts in section of a scraper embodying the present invention with the scraper shown in its normal position for transporting a scraper load;

Fig. 2 is a view in side elevation with parts in section of a scraper embodying the present invention illustrating the apron in its fully opened position with the ejector partially advanced as during the unloading operation;

Fig. 3 is a transverse sectional view taken along the line III-III of Fig. 1; and

Fig. 4 is a transverse sectional view taken along the line IVIV of Fig. 1.

In Fig. 1 of the drawings, a scraper of the type with which the present invention is used is illustrated as having a main bowl portion [0 including spaced side plates H and a bottom H, which at its forward end, is provided with a cutting edge l3. Adjacent its rear end, the bowl is provided with rearwardly extending frame members [4 which are supported on ground engaging wheels, only one of which is illustrated at [5 in Fig. 1. Intermediat its ends, the bowl is supported by a draft frame comprising spaced side arms l6 extending rearwardly from a tubular cross brace l1 and a forwardly extending draft arm l8. The spaced side arms [6 are pivotally connected by pins l9 to the bowl sides, and at its forward end, the draft arm 13 is supported by a universal connection (not shown) on a pair of ground engaging wheels 2|. Although it is not shown, the draft arm is provided with a suitable connection by means of which it may be connected to and drawn by a tractor or like vehicle in a conventional manner.

The scraper bowl is adapted to be lowered, bringing the cutting edge l3 into contact with the ground to effect collection of earth which is deposited in the bowl, as the scraper is drawn forwardly. Raising and lowering of the scraper bowl is accomplished by means of a single-acting hydraulically actuated jack indicated at 22 as anchored to and carried in the draft arm Ill. The jack is provided with an extending piston rod indicated at 23 connected to one end of a cable 24 extending about a guide sheave 26 supported for rotation in the draft arm, and at its opposite end is secured as at 21 to the forward end of the scraper bowl. Although it is not shown, the jack is adapted to receive fluid under pressure from a suitable pump and control valve carried by 3 the tractor and conveniently located to allow manipulation by th tractor operator in a conventional manner. During raising and lowering of the scraper bowl, the bowl and draft frame pivot about their respective supporting wheels and also hinge about the pins I 9.

The front of the scraper bowl is normally closed by an apron 28 which is provided with spaced rearwardly extending side arms 29 pivotally secured as by pins 30 to the sides of the scraper bowl to allow the apron to swing upwardly permitting loading and unloading of the scraper bowl. The rear of the scraper bowl is closed by an ejector 32 which is adapted to be moved forwardly through the scraper bowl to discharge the material collected therein. The ejector is supported for this movement by rollers 33 engaging guide rails 35, one of which is secured to each of the bowl side plates II. The ejector is guided for this reciprocating movement by a rearwardly extending carriage comprising braces 3! terminating in an inverted U-shaped housing 38 enclosing rollers 39 supported for rotation in the depending legs of housing 38. The rollers 39 engage guide rails 42, one of which is disposed on each side of a housing 43 supported on a cross beam. 44 forming a part of the main scraper frame.

The ejector 32 and apron 28 are actuated by a single double-acting jack comprising a piston 46 carried on a piston rod 4'! and adapted for reciprocation within a cylinder 48. lhe cylinder is disposed within the protecting housing 33 and is adaptedto receive fluid under pressure from the tractor driven pump (not shown) through conduits 49 and 50, one of which communicates with each end of the cylinder. The jack cylinder is pivotally supported by a pin 5| from the housing 43, and adjacent its extending end, the jack rod is supported by a pin 52 from a pair of spaced links 53. At their upper ends, the links 53 are supported for pivotal movement about a shaft 54 carried in spaced ears 55 extending rearwardly from the ejector. In the fully retracted position of the jack as is illustrated in Fig. 1, the end of the piston rod is spaced from the ejector, and the links 53 are provided to guide it toward a rearwardly extending abutment 55 provided on the ejector during extension of the jack under hydraulic pressure. After engagement of the end of the piston rod with the abutment, further extension of the jack advances the ejector throughv the scraper bowl.

The pin 52 supporting the piston rod 4'! also carries one end of a cam bar 5'! which is supported intermediate its ends by a roller 58 carried for rotation about a shaft 59 supported in the housing 38. The cam bar 5'! is provided with a notched portion 6! for the reception of a roller illustrated at 62 in Fig. 4 supported for rotation in a lever 54, which, at its opposite end, is rigidly clamped to a shaft 66 extending transversely across the rear of the scraper. The shaft 66 extends through and is supported for rocking movement in rearwardly extending parts of the scraper bowl sides ll. At each of its outer ends, the shaft 66 carries a lever 61 which is rigidly secured thereto as by anut 68, and, at its opposite end, is connected as by a pin 69 to a link H. As is best illustrated in Figs. 1 and 2, at their opposite ends the links H are connected by pins E2 to the side arms 29 of thebowl apron. The pins 12 are spacedfrom the pins 30. which form the pivotal supports for the apron so that upon for ward movement of links H, the apron will be 4 swung upwardly toward its open position as illustrated in Fig. 2.

In operation, the ejector and apron are actuated by directing fluid under pressure to cylinder 48 through conduit 49 moving the piston rod to the right as viewed in Figs. 1 and 2. During the first part of the piston rods movement from its fully retracted position illustrated in Fig. 1, the notch Bi in the cam bar 51 causes roller 62, lever 64, and shaft 66 to rock forwardly swinging the apron toward its open position. As the apron reaches its fully open position, the roller 62 clears the notch BI, and at the same time, the end of the piston rod engages the rearwardly extending abutment 56 provided on the ejector. Fur ther movement of the piston rod advances the ejector through the scraper bowl, and the apron is held in its fully opened position as illustrated in Fig. 2 by engagement of roller 62 with the upper edge of cam bar 51. During the time that the ejector is moving forwardly, the apron is locked in its fully opened position by engagement of roller 62 with cam bar, 5'1 and is not dependent on fluid pressure in the jack cylinder for holding it in its open position. As a result, the entire output from the fluid pump can be utilized for moving the ejector.

After the scraper bowl has been unloaded by advancing the ejector through the bowl, it is returned to its normal load-carrying position by retracting the piston rod 41. During the, initial movement of the piston rod away from the ejector, the cam bar 5'! moves relative to housing 38 until a projecting stop 13. on the under side of the cam bar engages roller 53 in the housing 38. After engagement of stop T3'with roller 58, fur,- ther movement ofv the piston rod toward its retracted position causes the ejector to move toward its load carrying position, and when the roller 62 enters notch 6|, the apron is permitted to swing downwardly to its closed position. It will, of course, be apparent that during loading of the scraper bowl, the apron may be raised or lowered to vary the opening above the scraping edge l3 by advancing the piston rod without advancing the ejector.

I claim:

1. In an earthmoving scraper having a bowl open at its forward end, a movable apron normal: 1y closing said open end, and an ejector advanceable through the bowl to eject the bowl contents through the forward end, a hydraulically actuated piston having an extending piston rod adapted to engage the ejector to advance it through the scraper bowl, operating linkage operatively connected to said apron to open the apron, and cam means carried by the piston rod engaging said apron operating linkage to open the apron before the piston rod engages the ejector.

2. In an earthmoving scraper having a bowl open at its forward end, a movable apron normally closing said open end, and an ejector advanceable through the bowl to eject the bowl contents through the forward end, a hydraulically actuated piston having an extending piston rod adapted to engage the ejector to advance it through the scraper bowl, operating linkage operatively connected to said apron toopen the apron, cam means carried by the piston rod, said cam means including a notched portion, and a lever in the apron operating linkage carrying a roller engageable insaid notched portion to effect opening of the apron before the piston rod engages the ejector.

3. In an earthmoving scraper having a bowl open at its forward end, a movable apron normally closing said open end, and an ejector advanceable through the bowl to eject the bowl contents through the forward end, a hydraulically actuated piston having an extending piston rod engageable with the ejector to advance it through the scraper bowl, operating linkage operatively connected to said apron to open the apron, cam means carried by the piston rod engaging said apron operating linkage to open the apron before the piston rod engages the ejector during movement of the piston rod toward the ejector, and means engageable by said cam to return the ejector from its advanced position during movement of the piston rod away from the ejector.

4. In an earthmoving scraper having a bowl open at its forward end, a movable apron normally closing said open end, and an ejector advanceable through the bowl to eject the bowl contents through the forward end, a hydraulically actuated piston having an extending piston rod engageable with the ejector to advance it through the scraper bowl, operating linkage operatively connected to said apron to open the apron, cam means carried by the piston rod engaging said operating linkage for opening the apron, said operating linkage including spaced link members pivotally secured to the apron, a shaft supported for rocking movement in the sides of the scraper bowl, levers carried by the shaft and connected to said links, and a second lever secured to the shaft intermediate said first mentioned levers and engageable by said cam means to actuate said apron in response to movement of said piston rod.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,223,829 LeBleu Dec. 3, 1940 2,303,650 Low Dec. 1, 1942 2,329,448 Austin Sept. 14, 1943 2,406,826 French Sept. 3, 1946 2,565,850 Hyler et al. Aug. 28, 1951 2,567,118 Murray Sept. 4, 1951 2,609,622 Murray Sept. 9, 1952 

